In Did You Know? the National Geographic magazine team shares extra information we gathered to expand your knowledge of our featured subjects.

Explorer John Wesley Powell completed his famous expedition down the Green and Colorado Rivers in 1869. But his life as one of America's great men of science was only just beginning. As an Indian commissioner, he became a student of the Pauite and Ute tribes, an interest that led in 1879 to the birth of the Smithsonian's Bureau of Ethnology, where he was director for 23 years. That same year he would be instrumental in the founding of the U.S. Geological Survey, the agency in charge of mapping the West, which he would head just two years later. At 47 he was perhaps the most powerful and influential scientist in America. His ideas for harnessing water in the West inspired the birth of the Bureau of Reclamation, and in 1888 he joined 32 scientists and prominent Washingtonians to establish the National Geographic Society. After his death in 1902 at the age of 68, he continued to influence government science: He donated his brain to research. It's preserved today at the Smithsonian Institution.